Blue vat dyestuff and process of making same.



"UNITED STATES PATENT OFFEFCE;

-301mm? wnnnn, on HfiCHST-ON-THE-MAIN, Ann BENNO non-0mm. or FRANKFURTon-rnn-mnm, GERMANY, ASSIGNORS T0 FARBWERKE vonivr Mnis'rnn- LUCIUS &BRt NING, or noclis'r-on-riin-mam, GERMANY; A CORPORATION or GERMANY.

BLUE VAT DYESTU'FF AND PROCESS OF MAKING SAME.

No Drawing.

To all whom it may -concern Be it known that we, ltoninzr YVnLon, Ph.1)., chemist, and Bnzsno lloMoLKA, Ph. 1)., chemist, citizens oftheEmpire of Germany, residing at HEichston-the-Main and Frankfort-onthe-lllain, Germany, respec tively, have invented certain new and use--ful Improvements in Blue Vat Dyestuffs and Processes of Making Same, ofwhich which crystallizes from'alboliol in the form of yellow needles; itdis solves in alkali lyes to a yellow solution which turns red onexposure to the air with\oxidation. Now, we have found that bycondensing the re duction-product of a-oxyanthraquinone with an isatinsubstituted in alpha-position, particularly with an isatin anilid or anisatin halogenid, valuable indigoid vat dyestuffs are obtained.

Example 1: 222 parts by weight of a-isatinanilid are heated on the waterbath with 210 parts of a-oxyanthranol, in about 1000 parts of aceticacid anhydrid, while stirring, until the separation of the coloringmatter is completed. The dyestufi, which is a dark'blue crystallinepowder resembling indigo, is filtered off, washed with acetic acid andWater and dried.

Example 2: 161 parts by weight of methyl-isatin (isatin of the tolueneseries) are-dissolved in benzene, toluene or Xylene and then convertedin known manner into the methylisatinchlorid by means of phosphorouspentachlorid, whereupon 210 parts of a-oxyanthranol' are added and themixture digested for some hours'at a low tem- Specification of LettersIatent.

Application filed January 20, 1911. Serial No. 603,653.

Patented May *7, 1912.

perature. The separated (.lyestull' is then treated as indicated inExample 1.

Similar dyestuffs are obtained by using the anilids or chloride ofisatins substituted inthe nucleus, for instance halogen-isatins,alkyloxy-isatins or the like.

The dyestuffs obtainable by the abovedescribed process are insoluble inwater, scarcely soluble. in alcohol, butreadily soluble in boilingXylene, phenol. nitrobenzene or the like to a blue to greenish-bluecolor. In concentrated sulfuric acid they dissolve to a violet-redsolution. When treated with alkaline reducing agents, the dyestuffs formorange-yellow vats which give on the fiber pureblue to greenish-bluetints.

Having now described our invention, what we claim is:

1. The process of making vat dyestuffs, which consists in causinganisatin substituted in alpha position to act upon oz-oxyanthranol. n

2. The vat dyestuit's hereinbefore described, being thecondensation-products ot' a-oxyant-hranol with an isatin substituted inalpha position, said dyestuft's being indigoblue crystalline powders,insoluble in water,

very little soluble in alcohol, readily soluble with a blue color inboiling xylene, phenol and nitrobenzene, also soluble with a violetcolor in concentrated sulfuric acid, and dissolving when treated withalkaline reducing agents, with an orange-yellow color.

3. The vat dyestutf hereinbefore described, being the condensationproduct of a-oxyanthranol with or-isatin anilid, said dyestufi being anindigo-blue crystalline powder, insoluble in water, very little solublein alcohol, readily soluble with a blue color in boiling xylene, phenoland nitrobenzene, also soluble with a violet color in concentratedsulfuric acid, and dissolving! when treated with alkaline reducingagents, with an orange-yellow color.

In testimony whereof, we atlix our signatures in presence oiftwowitnesses.

ROBERT WELDE. BENNO HQMOLKA.

